Changed sparkplugs today - comments on old ones?

[Hugo_za]

Hi Folks,

Finally received the socket required to change the plugs on the 6er. Did it this morning, and it was a fairly quick and painless job. Old plugs don't look great, and right after I put everything back together took the car for a drive and had a misfire on cylinder 8. Now, my car has been having some random misfire issues which is why I decided to swap out the plugs and coils. Only injectors left to check (will use an endoscope to check the index numbers). ISTA did also report that the fuel pressure on bank one did not pass the diagnostic test, but the cylinder specific tests did not show any issues with the injectors :confused2

Anyway, photo of the old plugs below. Viewer link for full resolution: https://ibb.co/QKF3NGy

Grateful for any feedback.
H

 

[Twinz]

Its hard to look at pictures of a plug.
But if the tips were dry and not alot of carbon buildup on the tip and no carbon tracking on the porcelain side and no excessive smell of fuel or oil on the plug tips then from the mere look of your pix the plugs look like they had a clean burn. Plugs 2 & 7 look a little rich but normal to me...unless they were wet due to fuel or oil but only you would know. Cant see carbon or corrosion...but as said before, pix are not very clear.

When you install the new plugs smear a little dielectric grease on the porcelein side (only) to prevent plugs from fusing and arching at the boots of the coil and therefore prevent misfires too.

 

[Peter@AEW]

Difficult with such a small pic.
2/4/7 look iffish

Enlarge and post

 

[Hugo_za]

Full res pic attached.

 

[Mamboza]

Put back old plugs and see if car still misfires.
Sometime last year i changed plugs, had misfire that we could not trace only to find problem was with new plugs.

Sent from my SM-G950F using Tapatalk

 

[Twinz]

How often do you replace your plugs? The plugs in the pix have been in your car too long. Plug two is busted and you can see corrosion/errosion on 1, 6, 7, 8.

Plug 2 is wet. Did it smell like fuel? That could be cylinder with the leaky injector....?

Try shorten the replacement to 5 - 7000ks if your is a high performance car.

 

[Twinz]

Why you say the OP must put old plugs back?? They done.

Replace them.
Then check coils by swopping them around in the cylinders to see if the misfire follows the coil...if not then check the injectors.

 

[Hugo_za]

This is the culprit. The new plug I installed on cylinder 8 seems to be faulty. Swapped plugs and coils between 7 and 8 and the misfire followed to no 7 along with lumpy acceleration just before the car went into limp. Put one of the better looking old plugs back and presto, no limp, no misfire and no my lumpy acceleration.

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I also checked the injectors with an endoscope today. All of them are index 09. I re-entered all their adaption values in ISTA and did a cylinder purge. Immediately noticed how the smell of the exhaust gas went from fuel-rich to smelling no worse than water vapour.

 

[Twinz]

Glad its sorted. Your "new" plugs look old too...you bought from BMW?